Electrical connector

ABSTRACT

An electrical connector for flat circuit bearing elements such as printed circuit boards as provided and includes an insulating housing with exterior surfaces including front and rear faces and a pair of elongated channels extending from the front face rearwardly into the housing for receiving the printed circuit boards, the rear face of the housing including a plurality of apertures extending into the housing for electrical access to the interior of the housing, and a plurality of metallic contacts including active portions spaced along and extending into the channels for engagement with conductive elements on the printed circuit boards and bridging portions interconnecting pairs of active portions in the housing, with at least one bridging portion overlying a second bridging portion with respect to the rear face and including an aperture aligned with one of the apertures from the rear face to provide electrical access to the underlying bridging portion.

United States Patent Occhipinti et a1.

[ Dec. 11, 1973 ELECTRICAL CONNECTOR [75] Inventors: Carl Occhipinti,Melrose Park; Irvin Richard Triner, Stickney, both of ill.

[73] Assignee: Bunker Ramo Corporation, Oak

Brook, Ill.

[22] Filed: May 5, 1972 [21] Appl. No.: 250,547

[52] US. Cl. 339/156 R, 339/151 B, 339/176 MP [51] Int. Cl. H051: 1/07[58] Field of Search 339/18 R, 18 C, 108 TP, 339/149 P, 150 B, 151 B,156, 176 MF,176 MP, 17 R, 17 E, 17 F, 17 L, 17 LC, 17 LM,

Primary ExaminerMarvin A. Champion Assistant Examiner-Lawrence J. StaabAttorney-Frederick M. Arbuckle [57] ABSTRACT An electrical connector forflat circuit bearing elem n u h as Printed 9599 b ards i P ovi andincludes an insulating housing with exterior surfaces including frontand rear faces and a pair of elongated channels extending from the frontface rearwardly into the housing for receiving the printed circuitboards, the rear face of the housing including a plurality of aperturesextending into the housing for electrical access to the interior of thehousing, and a plurality of metallic contacts including active portionsspaced along and extending into the channels for engagement withconductive elements on the printed circuit boards and bridging portionsinterconnecting pairs of active portions in the housing, with at leastone bridging portion overlying a second bridging portion with respect tothe rear face and including an aperture aligned with one of theapertures from the rear face to provide electrical access to theunderlying bridging portion.

9 Claims, 9 Drawing Figures PATENIED DEC! 1 I975 sazazurz ELECTRICALCONNECTOR BACKGROUND OF THE INVENTION Electrical connectors for flatcircuit bearing elements such as printed circuit boards having aplurality of conductive pads commonly are constructed of an insulatinghousing with one or more long, narrow channels on a front face and aplurality of metallic contacts with mounting portions rearwardlydisposed internally in the housing. Active'portions on the contacts arespaced along one or both sides of each of the channels to electricallyengage conductive pads spaced along one or more edges of the printedcircuit board when inserted into the channels.

In those connectors having a pair of parallel channels extendinglongitudinally between opposite external sidewalls, the contacts areoften arranged along both sides of the channels so as to form twocentrally located inner rows and two laterally separated, oppositelydisposed outer rows of contacts. With respect to one or more adjacentexterior longitudinal side surfaces, the outer contacts cover or overliecorresponding portions of the inner contacts. Although generallysatisfactory for many purposes, this arrangement of contacts limitselectrical accessibility to the underlying inner contacts from thoseexterior surfaces, thereby reducing the usefulness of the connectors fortest and other purposes.

In addition, it has been desirable in the multichanneled connectors toelectrically interconnect various combinations of oppositely positionedcontacts in the same channel or different channels without firstremoving the printed circuit boards. While these connections can be madethrough the use of external conductors, internal interconnection can bean advantage with respect to cost, insulative protection, and otherfactors; However, if other contacts are in the direct path between thosecontacts to be interconnected, maintaining the insulative protection ofthe intermediate contacts becomes a problem.

A further problem with these electrical connector involves the sometimesconflicting requirements of adequate mounting of the contacts in theinsulative housing and adequate interconnecting of opposed contacts.Frequently, the contact mounting portion is constructed of a thin,narrow metallic strip and is rigidly secured in the connector to supporta movable cantilever beam in the active portion. If the width of acontact mounting portion is reduced to permit opposite contacts to beinterconnected, the effectiveness of this mounting portion as a rigidsupport for the movable beam can be significantly limited.

As the above factors are considered in the construction of theconnector, other problems are encountered. These relate to thedesirability of constructing an insulative housing of a limited numberof parts while providing ease in mounting the contacts andadvantageously providing interconnections between contacts prior totheir mounting in the connector. In some instances, it is also desirableto provide limited accessibility to the inner contacts for test andother purposes while permitting increased accessibility under othercircumstances.

In view of the above, it is desirable to provide new electricalconnectors with features providing one or more of the advantagesdescribed herein.

SUMMARY OF THE INVENTION This invention relates to an electricalconnector in which portions of one or more contacts overlie portions ofother contacts in respect to an exterior surface of the connector andelectrical access is provided to the underlying portions withoutelectrically engaging the overlying contacts. More particularly, theinvention relates to an electrical connector provided with amultiplicity of electrical contacts arranged along opposite sides of twoor more long, narrow channels adapted to receive flat circuit bearingelements and in which at least a portion of the electrical contacts areinterconnected internally in the housing.

The connector includes an insulating housing with exterior surfacesincluding a front face provided with a cavity formed as one or morechannels to receive one or more printed circuit boards in a conventionalmanner. A plurality of metallic contacts are carried by the housing andinclude active portions arranged along each channel to engage conductiveelements on a printed circuit board during insertion into the channel.At least two of the contacts include portions disposed within thehousing with one of the contact portions overlying the other withrespect to an adjacent exterior surface.

The adjacent exterior surface of the housing includes a plurality ofapertures extending transversely from the surface into the housing toprovide electrical access to contact portions for test or otherpurposes. Preferably, the overlying contact portion includes an accessportion with an aperture aligned with one of the apertures in thehousing to permit access to the underlying contact portion. Preferably,the aperture in the contact portion-is a size larger than the aperturein the housing to prevent inadvertent simultaneous electrical engagementwith both contact portions.

Advantageously, the connector is constructed to include these fourcontacts arranged in two pair of contacts, with each pair beinginterconnected by an electrical bridge. One of the bridges is arrangedto overlie the other and contains an aperture of sufficient size andformed to align with one of the apertures in the housing to provideelectrical access to the underlying bridge portion of the contact pair.

Advantageously, the overlying bridge forms part of a one-pieceelectrical element which includes a pair of spaced-apart metalliccontacts with active portions for engagement with conductive elements ona printed circuit board, and interconnecting bridge portion providing anelectrical path between the active portions, and an access portion withan aperture in an arrangement and of sufficient size to permitelectrical access to the underlying portion of another conductiveelement in the housing.

Preferably, the one-piece electrical element also includes a pluralityof spaced-apart mounting means which coact in rigidly securing each ofthe two contacts in the insulative housing. Guide means are alsoprovided in the insulative housing through which the contacts can beinserted and their action portions bi-" ased in respect to the cavityforming the channels.

The electrical connector of the invention includes a number ofadvantages. A plurality of printed circuit boards can be mounted in theconnector and portions of their circuits can be internallyinterconnected. In addition, electrical access is individually providedto the inner and outer contacts from exterior surfaces in which theouter contacts essentially cover substantial portions of the innercontacts. Also, each of the pairs of contacts can be electricallybridged prior to being assembled in the connector by the use of theone-piece electrical element. A further advantage is that a plurality ofmounting means are provided on each bridged pair of contacts and coactto securely position the contacts in the connector. Guide tracks arealso provided to guide the active portions of the contacts frontwardlyin the connector during rear mounting of the contacts.

In addition to the above advantages, the connector includes a releasablecover which provides both limited and increased electrical accessibilityto the bridged inner and outer contacts. The cover also includes indiciain association with a plurality of access apertures to identify thecontacts accessible by the apertures. A further advantage of the coverconstruction is its recessed surfaces in alignment with openings in theconnector through which a wedgelike tool can be inserted for removingthe cover from the insulative housing.

DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a perspective view partially in cross section of an electricalconnector of the invention.

FIG. 2 is the cross-sectional view in FIG. 1 without the interconnectedpairs of contacts being positioned in the connector.

FIG. 3 is a reduced side view of the electrical connector of FIG. 1.

FIG. 4 is a partial view of the underside of the connector of FIG. 1.

FIG. 5 is a side view of a bridged pair of inner contacts shown in FIG.1.

FIG. 6 is an end view of the contacts shown in FIG. 5.

FIG. 7 is a rear view of the contacts shown in FIG. 5.

FIG. 8 is a rear view of a bridged pair of outer contacts shown in FIG.1.

FIG. 9 is a rear view of a rear cover plate with apertures and indiciato identify underlying contacts.

DETAILED DESCRIPTION The electrical connector of the invention comprisesan insulating housing having exterior surfaces including front and rearfaces and a pair of elongated channels extending from the front facerearwardly into the housing for receiving printed circuit boards. Therear face includes a plurality of apertures extending into the housingfor electrical access to the interior and with a plurality of metalliccontacts mounted therein. Active portions are provided on the metalliccontacts and are arranged to extend into each channel for engagementwith conductive elements on the printed circuit board.

More specifically, the connector includes a plurality of long, narrowchannels which are open at the front face of the insulating housing andextend rearwardly into the housing. A plurality of metallic contacts aremounted internally in the housing and include active portions spacedalong each of the longitudinal sides of the channels. Advantageously,each pair of the metallic contacts is interconnected by an electricalbridge portion which is disposed rearwardly in the connector housing,extends laterally between contacts in a direction parallel to the frontface of the housing, and combines with active portions to form aone-piece electrical element.

An insulating cover is provided on the housing to protect portions ofthe electrical bridges from accidental electrical connection by externalconductors. However, access to the protected electrical bridges isobtained by a pattern of apertures arranged on the rear cover withadjacent indicia to enable electrical access to individual electricalbridges in the connector and to identify those contacts. While the coveris adapted to be securely fastened in the insulating housing, recessedsurfaces in the cover are aligned with adjacent cutout wall sections ofthe insulating housingto enable the release of the cover at appropriatetimes. Advantageously, these form slits adaptable to receive a wedgeliketool to force the cover means away from the insulating housing.

Metallic contacts are rearwardly mounted in the housing and are securedby inwardly tapered barbs on each of the mounting portions of thecontacts. The mounting portions are disposed rearwardly in the housingand extend frontwardly therefrom in a direction generally normal to thefront face. Advantageously, they are forwardly disposed in respect tothe electrical bridge portion and securely fasten the interconnectedcontacts in the housing. .The active portion on each contact extendsfrontwardly from the mounting portion and comprises a bifurcated,yieldable, free-standing bow interconnected to the mounting portion by abifurcated ribbon inclined rearwardly from the bow to position the boweither inwardly or outwardly in respect to the mounting portiondepending on whether the contact will be inserted in the inner or outerlongitudinal sides of the channels. Frontwardly extending from thefree-standing bow is a bifurcated free-ended flat tip with oppositecoplanar ears adapted to bear against shoulders in the contact pocketsto preload the bow in respect to its associated channel.

The connector includes a plurality of spaced-apart, U-shaped barrierwalls aligned longitudinally along each channel with cutout portionsaligned longitudinally to form a central slot. The surfaces of thebarrier walls adjacent the slot extend laterally therefrom to form withsurfaces of adjacent barrier walls, contactreceiving pockets in whichthe contacts are mounted and loaded. Opposite surfaces of each pocketare stepped to form a plurality of guide tracks to guide the activeportion into the connector during assembly of the contacts. The pocketsextend rearwardly in the connector housing and serve to receive thepreviously interconnected pairs of contacts. Each pair of interconnectedcontacts is advantageously rearwardly mounted in the insulating housingin which a dummy printed circuit board has been previously inserted.

In the mounting operation, the active portions of each pair of contactsare inserted in guide tracks of their respective oppositely disposedpockets and forced frontwardly. The free-standing bow bears against thedummy board which prevents the bow from laterally entering into itsassociated slot. In the rear portion of each pocket are providedmounting surfaces laterally separated from the slot adjacent a flat sideof a channel which serves as a support wall for the barbed mountingportion. As the active portion becomes frontwardly disposed in theconnector, the barbs bite into the mounting surfaces and secure eachinterconnected pair of contacts in the connector housing. The dummyboard front face 12, rear face 17, and sidewall sections 13-16 enclosingcavity 18. Cavity 18 is divided by bar 19 which longitudinally extendsinternally between walls 13 and 16 and from front face 12 to rearsurface 17 to divide cavity 18 into channels 20 and 21. Openings 22provide equivalent cooling of each side of channels 20 and 21 to limitinternal stresses.

Also provided in the insulating housing are a plurality of spaced-apart,U-shaped barrier walls 23 disposed longitudinally along sidewalls 24-25of channel and sidewalls 26-27 of channel 21 and extending inwardlytherefrom in opposite directions. As illustrated, adjacent barrier walls23 form oppositely disposed contact pockets 28 with parts of guidetracks 29 and 30. The extremities of wall sections 14-15 are providedwith internal undercut sections 31 and 32 adapted to fasten rear cover33 over rear surface 17 of housing 10.

A plurality of spaced-apart contacts are disposed along each of thesidewalls 24-27 and include pairs of opposed inner contacts 34-35 andpairs of opposed outer contacts 36-37. Each of the contacts 34-37include a mounting portion with a central web 38 and coplanar oppositelydisposed mounting barbs 39-40 (more clearly illustrated in FIGS. 5-6).Extending frontwardly from each mounting portion is an active portion 41which includes a bifurcated inclined ribbon 42, bow 43 and upper tip 44with oppositely disposed coplanar ears 45-46.

Inner contacts 34-35 include an interconnecting electrical bridge 47illustrated as a flat strip apertured at 48 and aligned with opening 49in bar 19 to provide support for a test probe (not illustrated). Outercontacts 36-37 are also interconnected by rearwardly disposed electricalbridge 50 apertured at 51-52 to similarly provide support for testprobes (not illustrated). Electrical bridge 50 is separated from andoverlies inner bridge 47 with respect to rear surface 17. Cover 33includes apertures 53-54 respectively positioned to aligned relationshipover apertures 48 and 51 to provide electrical access thereto. In FIG.1, cover 33 is not apertured over aperture 52 since bridge 50 isaccessible by aperture 54.

U-shaped barrier wall3 23 are of stepped construction to provide guidetracks 29-30 for bow sections 43 and upper tips 44 of the contacts. Eachof the barrier walls includes two legs 55-56 with inner surfaces 57-58and a central web 59 forming the U-shape. Surfaces 57-58 and web 59 ofeach of barrier walls 23 form cutout portions aligned longitudinally inchannels 20 and 21 to form element-engaging slots 60-61.

In assembling contacts 34-37 in housing 10, the inner pair of contacts34-35 with integral electrical bridge 47 are rearwardly inserted inguide tracks 29-30 with bow sections 43 being restrained from enteringslots 60-61 by the presence of a dummy circuit board (not illustrated).Barbs 39-40 are forced forwardly and bite into adjacent surfaces 62-63to rigidly secure the contacts in pockets 28. Channel sides 24-27 adjoinwebs 38 to prevent their radial movement in pockets 28.

Outer pair of contacts 36-37 with electrical bridge 50 is then insertedin outer pockets 28 with barbs 39-40 similarly engaging adjacentsurfaces 64-65. As illustrated, outer contacts 36-37 include an extendedmounting portion 66 causing electrical bridge 50 to be rearwardlydisposed and electrically separated from inner electrical bridge 47. Thedummy board is then removed causing bow sections 43 to resiliently moveinto slots 60 and 61 and be biased inwardly in respect thereto by ears45-46 which bear against shoulders 67 and 68 on adjacent barrier walls23. As illustrated in FIG. 1, each leg of a U-shaped barrier wall 23 isgenerally T-shaped with the stem 69 extending from sidewall 14 withcross member 70 forming the side of the slot and tightly tapered at thefront face 12 of housing 10 to guide the printed circuit board into slot61. Grooves 72 extend from front face 12 on cross member 70 rearwardlyon each opposite pair of leg sections to provide a receptacle forinsertion of a polarizing key (not shown).

FIGS. 5-7 are illustrations of side, end, and rear views respectively ofthe pair of inner contacts 34-35 with electrical bridge 47. Each of thecontacts 34-35 and included electrical bridge portion 47 are constructedof a nickel alloy commonly identified as nickel silver. As illustrated,bridge 47 is provided with extrusion 73 for support of an external probe(not illustrated). Contact 35 includes a mounting portion with barbs39-40 for rigidly securing the contact in housing 10 and an activeportion with an outwardly inclined ribbon 42 forming a lower leg of bow43 and upper tip 44 with oppositely disposed coplanar ears 45-46. Asillustrated, barbs 39-40 laterally extend beyond ears 45-46 to permitthe insertion of the active portion into the contact pocket 28 with wallsections 62-63 of the pocket providing mounting surfaces for thecontact.

Electrical bridge 50 as illustrated in FIG. 8 includes apertures 51-52and frontwardly directed extrusions 74-75 (illustrated in FIG. 1) forinsertion and support of test probes. As illustrated in FIG. 1,apertures 51-52 are positioned in cavity 18 between adjacent barrierwalls 23 and therefore no additional openings are required in housing10. While electrical bridge 50 is rearwardly separated from bridge 47,electrical access to the frontwardly disposed bridge 47 is provided byaccess aperture 76 which is considerably larger than test probeapertures 48 and 51-52. In this manner, a test probe can be rearwardlyinserted into the connector housing 10, pass through aperture 76 withoutelectrically contacting bridge 50, and reach aperture 48, therebycontacting bridge 47 and associated contacts 34-35. Since accessaperture 76 extends laterally across a substantial portion of bridge 50,strengthening ribs 77-78 extending parallel to longitudinal axis 79 areprovided to resist flexural movement of bridge 50.

The test probe features of FIGS. 1 and 8 can also be utilized whereseparate tabs are provided in place of bridge 47 for contacts 34-35; inwhich event, separate apertures corresponding to aperture 48 areprovided in each tab with each aperture aligned with access aperture 76.

The support arrangement for bridges 47 and 50 is illustrated in FIGS.1-2 and 4. For support of bridge 47, central bar 19 is provided withrear surface 79 parallel to front face 12 and extending longitudinallyalong sides 25-26 of channels 20-21. Adjoining bridges 47 are separatedby ridges 80 extending laterally between channel sides 24 and 27 andrearwardly raised from rear surface 79. in the molding of housing 10,ridges 80 are integrally formed with central bar 19 and U-shaped barrierwalls 23. In channels 20-21, ridge 80 is rearwardly raised from therearward extremity 81 of central webs 59 which include shoulders 82-83as mounting surfaces for supporting electrical bridge 50. Shoulders82-83 are slightly rearwardly disposed in respect to rear surface 79 ofcentral bar 19 to provide electrical separation between bridges 47 and50 while ridge 80 provides electrical insulation between adjoiningbridges 50.

Extending rearwardly from barrier walls 23 are wall sections 84-85 asillustrated in FIGS. 3-4 with rear edges 89-90. In FIG. 3, wall section85 is provided with notches 86-88 with wall section 84 being similarlynotched for access to cover 33.

Adjacent to each of the notches 86-88 are undercut portions 91-93 whichare conveniently provided in the molding operation by grooves 94-96extending rearwardly from front face 12 of housing 10. insulating cover33 is disposed within wall sections 84-85 and provides protectionagainst accidental external electrical connection ridges 47 and 50. Asillustrated in FIG. 9, cover 33 includes along each of its longitudinaledges 97-98 nibs 99-101 and 102-104 to snap into undercut portions 91-93(FIG. 3) and corresponding undercut portions on wall section 84.Longitudinal edges 97-98 are also provided with recesses 105-107 and108-110 which align with notches 86-88 and corresponding notches in wallsection 84. Projections 111-112 are provided on edge 98 to properlyorient cover 33 in housing 10, although nibs 102-104 on edge 98 can belocated in a different pattern than that of nibs 99-101 on edge 97 toprovide the desired orientation of cover 33. When cover 33 is properlypositioned within wall sections 84-85, the recesses are aligned withcorresponding notches and permit the insertion of a wedgelike tool intothe recesses to release cover 33 in the event that inspection is desiredof the electrical bridges. This feature also permits replacement of oneor more pairs of contacts.

As further illustrated in FIG. 9, cover 33 includes two parallel rows ofapertures 113-114 and adjacent indicia 115-116, the latter serving toidentify each bridged pair of electrical contacts in respect to theother contacts. When cover 33 is inserted in the housing, apertures 113are aligned with apertures 52 of bridge 50 while apertures 114 arealigned with apertures 48 on bridges 47. in respect to cover 33, ridges79 serve to separate cover 33 slightly from bridges 50.

The foregoing description of the present invention is only illustrativeof an exemplary form which the invention may take. Still othermodifications and variations will suggest themselves to persons skilledin the art. It is intended, therefore, that the foregoing detaileddescription be considered as exemplary only and that the scope of theinvention be ascertained from the following claims.

We claim:

1. An electrical connector adapted to receive external electricalelements in electrical engage-ment and comprising an insulating housingincluding exterior surfaces,

a plurality of metallic contacts carried by said housing and arranged toengage said elements,

at least four of said contacts being arranged in first and secondcontact pairs with respective first and second electrical bridges, saidbridges being spaced apart within said housing and in overlyingrelationship with respect to one of said surfaces, said first bridgebeing close to said one surface and including a first aperture extendingthrough said bridge, and

said housing including a second aperture extending transversely fromsaid one surface to said first aperture and beyond to said second bridgeproviding electrical access to said second pair of contacts.

2. The electrical connector of claim 1 wherein said first aperture islarger than said second aperture.

3. The electrical connector of claim 1 wherein said housing includes atleast one cavity extending from a second of said surfaces into saidhousing and providing access to said contacts by said externalelectrical elements.

4. The electrical connector of claim 1 wherein said exterior surfacesinclude front and rear faces, said housing includes a cavity extendingfrom said front face rearwardly into the housing and bar means dividingand separating said cavity into two channels, and said contacts includeactive portions extending into said channels for engagement with saidexternal electrical elements.

5. The electrical connector of Claim 4 wherein said insulating housingincludes wall sections extending between said front and rear faces andenclosing said cavity with said bar means longitudinally extendingbetween opposite wall sections and from said front face rearwardly to arear surface in said cavity to form said two channels,

a plurality of spaced-apart barrier walls disposed longitudinally alongeach channel and laterally interconnecting said bar means and one ofsaid wall sections in each channel, said barrier walls in said twochannels including longitudinally aligned cutout portions to define twoslots adapted to receive a flat circuit bearing element, said barrierwalls extending between front face of said cavity rearwardly a distancebeyond said rear surface of said cavity and having rear mountingsurfaces,

a plurality of said first and second pairs of contacts mounted in thehousing with said second bridge of each second pair being disposed onsaid rear surface of said bar means and said first bridge of each firstpair being disposed on said rear mounting surfaces of adjacent barrierwalls and overlying one of said second bridges, said wall sectionsextending rearwardly from said barrier walls and having rear edges witha plurality of notches extending from said edges frontwardly, and

an insulating cover including a plurality of said second apertures andsaid insulating cover disposed within said wall sections, said coverhaving recesses aligned with said notches and adapted to receive awedge-like tool inserted through said notches to release said cover fromsaid connector.

6. A one-piece electrical element for insertion into an electricalconnector for engagement with external electrical elements, saidconnector including an insulating housing with exterior surfaces and aplurality of conductive elements, said one-piece electrical elementconstructed to overlie a portion of at least one of said conductiveelements with respect to one of said exterior surfaces and comprising apair of spaced-apart metallic contacts including active portionsarranged to engage said external conductive elements an interconnectingbridge portion providing an electrical path between said active portionsand including an access portion with at least one aperture extendingthrough the access portion and of sufficient size to permit electricalaccess from said one exterior surface through said aperture to saidconductive element, said bridge portion in-cluding reinforcing ribsadjacent said aperture. 7. The electrical element of claim 6 whereineach contact has a mounting portion including a flat ribbon allydisposed from said one aperture for receiving a test probe.

1. An electrical connector adapted to receive external electricalelements in electrical engage-ment and comprising an insulating housingincluding exterior surfaces, a plurality of metallic contacts carried bysaid housing and arranged to engage said elements, at least four of saidcontacts being arranged in first and second contact pairs withrespective first and second electrical bridges, said bridges beingspaced apart within said housing and in overlying relationship withrespect to one of said surfaces, said first bridge being close to saidone surface and including a first aperture extending through saidbridge, and said housing including a second aperture extendingtransversely from said one surface to said first aperture and beyond tosaid second bridge providing electrical access to said second pair ofcontacts.
 2. The electrical connector of claim 1 wherein said firstaperture is larger than said second aperture.
 3. The electricalconnector of claim 1 wherein said housing includes at least one cavityextending from a second of said surfaces into said housing and providingaccess to said contacts by said external electrical elements.
 4. Theelectrical connector of claim 1 wherein said exterior surfaces includefront and rear faces, said housing includes a cavity extending from saidfront face rearwardly into the housing and bar means dividing andseparating said cavity into two channels, and said contacts includeactive portions extending into said channels for engagement with saidexternal electrical elements.
 5. The electrical connector of Claim 4wherein said insulating housing includes wall sections extending betweensaid front and rear faces and enclosing said cavity with said bar meanslongitudinally extending between opposite wall sections and from saidfront face rearwardly to a rear surface in said cavity to form said twochannels, a plurality of spaced-apart barrier walls disposedlongitudinally along each channel and laterally interconnecting said barmeans and one of said wall sections in each channel, said barrier wallsin said two channels including longitudinally aligned cutout portions todefine two slots adapted to receive a flat circuit bearing element, saidbarrier walls extending between front face of said cavity rearwardly adistance beyond said rear surface of said cavity and having rearmounting surfaces, a plurality of said first and second pairs ofcontacts mounted in the housing with said second bridge of each secondpair being disposed on said rear surface of said bar means and saidfirst bridge of each first pair being disposed on said rear mountingsurfaces of adjacent barrier wallS and overlying one of said secondbridges, said wall sections extending rearwardly from said barrier wallsand having rear edges with a plurality of notches extending from saidedges frontwardly, and an insulating cover including a plurality of saidsecond apertures and said insulating cover disposed within said wallsections, said cover having recesses aligned with said notches andadapted to receive a wedge-like tool inserted through said notches torelease said cover from said connector.
 6. A one-piece electricalelement for insertion into an electrical connector for engagement withexternal electrical elements, said connector including an insulatinghousing with exterior surfaces and a plurality of conductive elements,said one-piece electrical element constructed to overlie a portion of atleast one of said conductive elements with respect to one of saidexterior surfaces and comprising a pair of spaced-apart metalliccontacts including active portions arranged to engage said externalconductive elements an interconnecting bridge portion providing anelectrical path between said active portions and including an accessportion with at least one aperture extending through the access portionand of sufficient size to permit electrical access from said oneexterior surface through said aperture to said conductive element, saidbridge portion in-cluding reinforcing ribs adjacent said aperture. 7.The electrical element of claim 6 wherein each contact has a mountingportion including a flat ribbon with opposite coplanar inwardly taperedbarbs adapted to mount rearwardly in said connector and each of saidactive portions include a yieldable free-standing bow and a flat tipoppositely disposed in respect to said mounting portion.
 8. Theelectrical connector of claim 1 wherein said first bridge includes atleast one test aperture laterally disposed from said first aperture forreceiving a test probe and said second bridge also includes at least onetest aperture.
 9. The electrical element of claim 6 wherein said bridgeportion includes at least one test aperture laterally disposed from saidone aperture for receiving a test probe.